"Fig. 1.(from Lindstrom and Meyer-Rochow 1987) Filter characteristics as supplied by the manufacturer: the solid line and the top abscissa refer to Kodak Wratten filter 87 while the broken line and bottom abscissa describe the transmittance of the O'Hara RT-2 filter used in the ""Find-R-Scope"" infra-red viewer/emitter."
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